I have a really cool idea, but it doesn't work

I'm making a film using ML/RAW. I want to process it using ACR in AE because it produces the most awesome image results I've seen so far.
I own a copy of Adobe CS5 and neither want to afford to buy an update nor pay their CC rental fees nor want to pirate a new copy.
So I'm looking for a workflow with my existing software that will let me use flicker-free ACR processing anyway.
After checking out the Flicker Free ETTR Time Lapse page (
http://www.magiclantern.fm/forum/index.php?topic=5705) I thought that individual XMP files for each DNG (identical file base name with .xmp extension) with a constant exposure attribute could maybe trick ACR into keeping a constant exposure when making heavy use of the Shadow and Highlight Recovery features on images with changing exposure.
However, when I write files of following content for each DNG, importing the sequence into AE will result in ACR image manipulations being applied only to the very first image of the sequence. All subsequent images will remain in their unpolished raw appearance.
This makes me believe that I could have made mistakes in creating the XMP files or its syntax, and that the idea in general could still work.
I tried both following file contents. One is basically the file created by the ML Post-Deflicker routine. The second has been extracted from a ACR-manipulated file, stripped of all attributes except the crs:Exposure.
Does anyone spot a mistake or know which attributes need to stay in the XMP code?
First try:
<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="Magic Lantern">
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<rdf:Description rdf:about=""
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:photoshop="http://ns.adobe.com/photoshop/1.0/"
xmlns:crs="http://ns.adobe.com/camera-raw-settings/1.0/"
photoshop:DateCreated="2050-01-01T00:00:00:00"
photoshop:EmbeddedXMPDigest=""
crs:ProcessVersion="6.7"
crs:Exposure2012="0.00">
<dc:subject>
<rdf:Bag>
<rdf:li>ML Post-Deflicker</rdf:li>
</rdf:Bag>
</dc:subject>
</rdf:Description>
</rdf:RDF>
</x:xmpmeta>
Second try:
<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="Adobe XMP Core 5.3-c007 1.136881, 2010/06/10-18:11:35 ">
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<rdf:Description rdf:about=""
xmlns:xmp="http://ns.adobe.com/xap/1.0/"
xmlns:xmpMM="http://ns.adobe.com/xap/1.0/mm/"
xmlns:stEvt="http://ns.adobe.com/xap/1.0/sType/ResourceEvent#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:crs="http://ns.adobe.com/camera-raw-settings/1.0/"
xmp:CreatorTool="Rarevision RAWMagic 1.0"
xmp:Rating="0"
crs:Exposure="0.00"
</rdf:Description>
</rdf:RDF>
</x:xmpmeta>